Systems and methods for a communication bridge between an implantable medical device and an external device

ABSTRACT

Systems and methods are provided for bridging a bi-directional communication link between an external device and an implantable medical device (IMD). The systems and methods establish a first bi-directional communication link between an external device and a wireless bridge device according to a wireless protocol, and establish a second bi-directional communication link between the wireless bridge device and an IMD concurrently with the first bi-direction communication link according to the wireless protocol. The systems and methods further receive a data packet from the external device at the wireless bridge device. The data packet is received during the communication interval. The systems and methods further transmit the data packet from the wireless bridge device to the IMD during the communication interval.

BACKGROUND OF THE INVENTION

Embodiments of the present disclosure generally relate to systems andmethods for a bi-directional communication link between devices, andmore particularly for a communication bridge between an implantablemedical device and an external device.

An implantable medical device (“IMD”) is a medical device that isconfigured to be implanted within a patient anatomy and commonly employone or more leads with electrodes that either receive or delivervoltage, current or other electromagnetic pulses (generally “energy”)from or to an organ or tissue for diagnostic or therapeutic purposes. Ingeneral, IMDs include a battery, electronic circuitry, such as a pulsegenerator and/or a microprocessor that is configured to handle RFcommunication with an external device as well as control patienttherapy. The components of the IMD are hermetically sealed within ametal housing (generally referred to as the “can”).

IMDs are programmed by and transmit data to external devices controlledby physicians and/or the patient. The external devices communicate byforming wireless bi-directional communication links with the IMDs.Recently, the IMD may communicate using commercial protocols such asBluetooth Low Energy (BLE), which are compatible with commercialwireless devices such as tablet computers, smartphones, and the like.However, commercial protocols communicate along a 2.450 gigahertzindustrial, scientific and medical (ISM) radio band which is susceptibleto interference. Particularly, the communications transmitted from theIMD along the ISM band suffers due to path attenuation as thetransmission propagate through the body of the patient. Thereby limitingthe communication range of the IMD with the external device, forexample, to less than a meter. A need exists for improved methods andsystems for extending the communication range of the IMD with theexternal device.

BRIEF SUMMARY

In accordance with an embodiment herein, a method is provided forbridging a bi-directional communication link between an external deviceand an implantable medical device (IMD). The method includesestablishing a first bi-directional communication link between anexternal device and a wireless bridge device according to a wirelessprotocol. The method further includes establishing a secondbi-directional communication link between the wireless bridge device andan IMD concurrently with the first bi-directional communication linkaccording to the wireless protocol. The method also includes receiving adata packet from the external device at the wireless bridge device. Thedata packet is received during the communication interval. The methodfurther includes transmitting the data packet from the wireless bridgedevice to the IMD during the communication interval.

In an embodiment, a wireless bridge device for bridging a bi-directionalcommunication link between an external device and an implantable medicaldevice (IMD) is provided. The wireless bridge device includes a housingand at least one antenna. The wireless bridge device also includes asystem on chip (SoC) within the housing electrically coupled to the atleast one antenna. The SoC includes one or more processors and isconfigured to establish a first bi-directional communication link withan external device according to a wireless protocol. The SoC is alsoconfigured to establish a second bi-directional communication link withan IMD concurrently with the first bi-directional communication linkaccording to the wireless protocol, and receive a data packet from theexternal device via the at least one antenna during a communicationinterval. The SoC is also configured to transmit the data packet to theIMD via the at least one antenna during the communication interval.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates simplified block diagram of a system for initiating abi-directional communication link, according to an embodiment of thepresent disclosure.

FIG. 2 illustrates a block diagram of exemplary internal components ofan implantable medical device, according to an embodiment of the presentdisclosure.

FIG. 3 illustrates a block diagram of exemplary internal components ofan external device, according to an embodiment of the presentdisclosure.

FIG. 4A illustrates a block diagram of exemplary internal components ofa wireless bridge device, according to an embodiment of the presentdisclosure.

FIG. 4B illustrates a block diagram of exemplary internal components ofa wireless bridge device, according to an embodiment of the presentdisclosure.

FIG. 5 illustrates a flowchart of a method for bridging a bi-directionalcommunication link between an external device and an implantable medicaldevice.

FIG. 6 illustrates a timing diagram to establish a communication link,according to an embodiment of the present disclosure.

FIG. 7 illustrates a timing diagram between an external device, awireless bridge device, and an implantable medical device, according toan embodiment of the present disclosure.

FIG. 8 illustrates a flowchart of a method for bridging a bi-directionalcommunication link between an external device and an implantable medicaldevice.

FIG. 9 illustrates a block diagram of exemplary internal components ofan implantable medical device, according to an embodiment of the presentdisclosure.

DETAILED DESCRIPTION

While multiple embodiments are described, still other embodiments of thedescribed subject matter will become apparent to those skilled in theart from the following detailed description and drawings, which show anddescribe illustrative embodiments of disclosed inventive subject matter.As will be realized, the inventive subject matter is capable ofmodifications in various aspects, all without departing from the spiritand scope of the described subject matter. Accordingly, the drawings anddetailed description are to be regarded as illustrative in nature andnot restrictive.

Various embodiments described herein include a method and/or system forbridging a bi-directional communication link between an external deviceand an implantable medical device (IMD). For example, a wireless bridgedevice is configured to relay wireless transmissions between theexternal device and the IMD. The wireless bridge device may firstestablish a communication link with the external device configured as amaster and the wireless bridge configured as a slave. The wirelessbridge device may receive connection information (e.g., serial number)corresponding to the IMD. Based on the connection information, thewireless bridge device may establish a communication link, configured asa master, with the IMD configured as a slave. Thereby, the wirelessbridge may concurrently include two communication links between theexternal device and the IMD. When the two communication links areestablished, the wireless bridge device may relay or pass information(e.g., data packets) received from the first device to the second deviceand vice versa.

The wireless bridge device is a mobile device, which may be positionedand/or repositioned within a room and/or on a patient to change theproximity of the wireless bridge to the IMD. For example, the wirelessbridge device may be repositioned closer to the IMD by positioning theIMD on a chest of a patient. The wireless bridge device may include asystem on chip (SoC) solution. The SoC may include a central processingunit (CPU) core (e.g., 8051, ARM cortex) with one or more analogcomponents (e.g., amplifiers, analog to digital converters, filters,digital to analog converters), memory (e.g., EEPROM, RAM, ROM, Flash),transceiver, and/or the like. The CPU core executes instructions storedon the memory to perform one or more applications. For example, the SoCmay be configured to establish communication links with one or moreother devices (e.g., the external device, the IMD) according to awireless protocol, such as a Bluetooth Low Energy (BLE), Bluetooth,ZigBee, or the like. Additionally or alternatively, the SoC may beconfigured to implement security protocols (e.g., encryption algorithms,one or more message authentication codes) and/or software rules whenestablishing and/or transmitting data along one or more communicationlinks.

Optionally, the SoC may be a BLE SoC configured for establishingbi-directional communication links and transmitting and/or receivingdata according to the BLE protocol. The BLE protocol is defined within“Bluetooth Specification Version 4.1, published Dec. 3, 2013(incorporated herein by reference). The BLE protocol is a master-slaveprotocol operating within a frequency range of 2400-2483.5 MHz(including guard bands). However, the BLE protocol uses 40 RF channelsusing a 2 MHz bandwidth. The 40 RF channels are allocated into twochannel types, a data channel (having 37 channels) and an advertisingchannel (having 3 channels). The data channel is used by devices on aBLE network for communication between connected devices. The advertisingchannel is used by devices on the BLE network to discover new devices,initiating a connection, and broadcasting data. Each RF channel (dataand advertising channel) is allocated a unique channel index, such that,if two devices wish to communicate, the transceivers of each device mustbe tuned to the same RF channel at the same time.

Data transmitted on the RF channels are grouped into data packets. Thedata packets are transmitted at 1 Mbps and include four entities, apreamble, an access address, a protocol data unit (PDU), and a cyclicredundancy check (CRC). The preamble contains 8 bits and is used by thereceiver to perform frequency synchronization, symbol timing estimation,and automatic gain control training. The access address contains 32bits. The access address for all advertising channel data packets ispredetermined by the BLE protocol. The access address in data channelpackets is generated by the device and is different for any two devicesusing the same data channel. The PDU contains a 16 bit header and avariable size payload. Optionally, the PDU for data channel data packetsmay contain a 32 bit Message Integrity Check field for use in encryptingdata packets.

Each device using the BLE protocol is designated either as a master or aslave device. The BLE protocol does not limit the number of slavedevices controlled or communicating with the master device. Oncecommunication is established, the master and the slave alternate sendingand receiving data packets during a connection event. The connectionevent may last between 7.5 ms to 4.0 s and beginning at an anchor point.The anchor point is derived on when the master device transmits a datachannel PDU to the slave device. Either the master or slave device mayclose or terminate the connection event.

A technical effect of various embodiments described herein extend thecommunication range and signal quality of the IMD in relation to thepatient. A technical effect of various embodiments described hereinprovide a wireless bridge device implemented on a single SoC reducingcost and complexity in firmware design.

FIG. 1 illustrates a simplified block diagram of a system 100 forbridging a bi-directional communication link between an external device201 and an implantable medical device (IMD) 101. The system 100 includesthe implantable medical device (IMD) 101 having a bi-directionalcommunication link 104 with a wireless bridge device 102, and theexternal device 201 (e.g., table computer, smart phone, laptop, or thelike) having a bi-directional communication link 105 with the wirelessbridge device 102.

The bi-directional communication links 104 and 105 may use any standardwireless protocol such as Bluetooth Low Energy, Bluetooth, Wireless USB,Medical Implant Communication Service, ZigBee, and/or the like thatdefine a means for transmitting and receiving information (e.g., data,commands, instructions) between devices. For example, the wirelessbridge device 102 may receive and/or transmit information to theexternal device 201 via the bi-directional communication link 105. Inanother example, the wireless bridge device 102 may receive and/ortransmit information to the IMD 101 via the bi-directional communicationlink 104.

The external device 201 may program the IMD 101 and/or receive data fromthe IMD 101 via the wireless bridge device 102, which provides acommunication bridge between the IMD 101 and the external device 201.For example, the external device 201 may transmit a request for datameasurements over the bi-directional communication link 105. The requestis received by the wireless bridge device 102, which relays (e.g.,transmits) the request for data measurements to the IMD 101 over thebi-directional communication link 104. In response to the request, theIMD 101 transmits the measurements to the wireless bridge device 102over the bi-directional communication link 104. The wireless bridgedevice 102 relays (e.g., transmits) the measurements to the externaldevice 201 over the bi-directional communication link 105.

In various embodiments, the wireless bridge device 102 may be portableand/or handheld device allowing the user to position and/or repositionthe wireless bridge device 102 within a room and/or in varyingproximities to the patient. For example, the wireless bridge device 102may be placed against an exterior surface of the patient 106, such asthe skin of a patient 106. Additionally or alternatively, the wirelessbridge device 102 may be mounted and/or integrated to a device proximateto the patient 106. For example, the wireless bridge device 102 may bemounted to a bed of the patient 106, a patient monitoring system, and/orthe like.

The IMD 101 may be implanted within the patient 106 (e.g., proximate toa heart 103, proximate to the spinal cord). Additionally oralternatively, the IMD 101 may have components that are external to thepatient 106, for example, the IMD 101 may include a neuro external pulsegenerator (EPG). The IMD 101 may be one of various types of implantabledevices, such as, for example, neurostimulator, electrophysiology (EP)mapping and radio frequency (RF) ablation system, an implantablepacemaker, implantable cardioverter-defibrillator (ICD), defibrillator,cardiac rhythm management (CRM) device, an implantable pulse generator(IPG), or the like.

FIG. 2 illustrates a block diagram of exemplary internal components ofthe IMD 101. The systems described herein can include or representhardware and associated instructions (e.g., software stored on atangible and non-transitory computer readable storage medium, such as acomputer hard drive, ROM, RAM, or the like) that perform the operationsdescribed herein. The hardware may include electronic circuits thatinclude and/or are connected to one or more logic-based devices, such asmicroprocessors, processors, controllers, or the like. These devices maybe off-the-shelf devices that perform the operations described hereinfrom the instructions described above. Additionally or alternatively,one or more of these devices may be hard-wired with logic circuits toperform these operations.

The IMD 101 is for illustration purposes only, and it is understood thatthe circuitry could be duplicated, eliminated or disabled in any desiredcombination to provide a device capable of treating the appropriatechamber(s) with cardioversion, defibrillation and/or pacing stimulationas well as providing for apnea detection and therapy. Additionally oralternatively, the IMD 101 may be used to generate electricalstimulation for application to a desired area of a body, such as aspinal cord stimulation, as described later herein corresponding to FIG.9.

The housing 138 for the IMD 101, shown schematically in FIG. 2, is oftenreferred to as the “can”, “case” or “case electrode” and may beprogrammably selected to act as the return electrode for all “unipolar”modes. The housing 138 may further be used as a return electrode aloneor in combination with one or more of the coil electrodes for shockingpurposes. The housing 138 further includes a connector (not shown)having a plurality of terminals, 142, 152, 154, 156 and 158 (shownschematically and, for convenience, the names of the electrodes to whichthey are connected are shown next to the terminals. A right atrial tipterminal (A_(R) TIP) 142 is adapted for connection to the atrial tipelectrode and a right atrial ring terminal may be adapted for connectionto right atrial ring electrode. A left ventricular tip terminal (V_(L)TIP) 144, a left atrial ring terminal (A_(L) RING) 146, and a leftatrial shocking terminal (A_(L) COIL) 148 are adapted for connection tothe left ventricular ring electrode, and a left atrial tip electrode anda left atrial coil electrode respectively. A right ventricular tipterminal (V_(R) TIP) 152, a right ventricular ring terminal (V_(R) RING)154, a right ventricular shocking terminal (R_(V) COIL) 156, and an SVCshocking terminal (SVC COIL) 158 are adapted for connection to the rightventricular tip electrode, right ventricular ring electrode, an RV coilelectrode, and an SVC coil electrode, respectively.

An acoustic terminal (ACT) 150 is adapted to be connected to an externalacoustic sensor or an internal acoustic sensor, depending upon which (ifany) acoustic sensors are used. Terminal 151 is adapted to be connectedto a blood sensor to collect measurements associated with glucoselevels, natriuretic peptide levels, or catecholamine levels.

The IMD 101 includes a programmable microcontroller 160 which controlsoperation. The microcontroller 160 (also referred to herein as aprocessor module or unit) typically includes a microprocessor, orequivalent control circuitry, designed specifically for controlling thedelivery of stimulation therapy and may further include RAM or ROMmemory, logic and timing circuitry, state machine circuitry, and I/Ocircuitry. Typically, the microcontroller 160 includes the ability toprocess or monitor input signals (data) as controlled by program codestored in memory. The details of the design and operation of themicrocontroller 160 are not critical to the invention. Rather, anysuitable microcontroller 160 may be used that carries out the functionsdescribed herein. Among other things, the microcontroller 160 receives,processes, and manages storage of digitized cardiac data sets from thevarious sensors and electrodes. For example, the cardiac data sets mayinclude IEGM data, pressure data, heart sound data, and the like.

The IMD 101 includes an atrial pulse generator 170 and aventricular/impedance pulse generator 172 to generate pacing stimulationpulses for delivery by the right atrial lead 130, the right ventricularlead 131, and/or the coronary sinus lead 132 via an electrodeconfiguration switch 174. It is understood that in order to providestimulation therapy in each of the four chambers of the heart, theatrial and ventricular pulse generators, 170 and 172, may includededicated, independent pulse generators, multiplexed pulse generators orshared pulse generators. The pulse generators, 170 and 172, arecontrolled by the microcontroller 160 via appropriate control signals,176 and 178, respectively, to trigger or inhibit the stimulation pulses.

The IMD 101 includes a neuro stimulation pulse generator circuit 192 togenerate stimulation pulses for a brain or spinal cord nervous system.The stimulation pulses are delivered by a plurality of electrodesthrough the neuro output lead 191. The neuro stimulation pulse generatorcircuit 192 is controlled by the microcontroller 160 via appropriatecontrol signals 193 to trigger or generate the stimulation pulses.

The microcontroller 160 further includes timing control circuitry 179used to control the timing of such stimulation pulses (e.g., pacingrate, atria-ventricular (AV) delay, atrial interconduction (A-A) delay,or ventricular interconduction (V-V) delay, etc.) as well as to keeptrack of the timing of refractory periods, blanking intervals, noisedetection windows, evoked response windows, alert intervals, markerchannel timing, and the like. Switch 174 includes a plurality ofswitches for connecting the desired electrodes to the appropriate I/Ocircuits, thereby providing complete electrode programmability.Accordingly, the switch 174, in response to a control signal 180 fromthe microcontroller 160, determines the polarity of the stimulationpulses (e.g., unipolar, bipolar, etc.) by selectively closing theappropriate combination of switches (not shown) as is known in the art.

Atrial sensing circuit 182 and ventricular sensing circuit 184 may alsobe selectively coupled to the right atrial lead 130, coronary sinus lead132, and the right ventricular lead 131, through the switch 174 fordetecting the presence of cardiac activity in each of the four chambersof the heart. Accordingly, the atrial (ATR SENSE) and ventricular (VTRSENSE) sensing circuits, 182 and 184, may include dedicated senseamplifiers, multiplexed amplifiers or shared amplifiers. The outputs ofthe atrial and ventricular sensing circuits, 182 and 184, are connectedto the microcontroller 160 which, in turn, are able to trigger orinhibit the atrial and ventricular pulse generators, 170 and 172,respectively, in a demand fashion in response to the absence or presenceof cardiac activity in the appropriate chambers of the heart.

Cardiac signals are also applied to the inputs of an analog-to-digital(A/D) data acquisition system 190. The data acquisition system 190 isconfigured to acquire IEGM signals, convert the raw analog data into adigital IEGM signal, and store the digital IEGM signals in memory 194for later processing and/or RF transmission along the bi-directionalcommunication link 104. The data acquisition system 190 is coupled tothe right atrial lead 130, the coronary sinus lead 132, and the rightventricular lead 131 through the switch 174 to sample cardiac signalsacross any combination of desired electrodes. The data acquisitionsystem 190 may also be coupled, through switch 174, to one or more ofthe acoustic sensors. The data acquisition system 190 acquires, performsA/D conversion, produces and saves the digital pressure data, and/oracoustic data.

The controller 160 controls the acoustic sensor and/or a physiologicsensor to collect heart sounds during one or more cardiac cycles. Theheart sounds include sounds representative of a degree of blood flowturbulence. The acoustic sensor and/or physiologic sensor collects theheart sounds that include S1, S2 and linking segments. The S1 segment isassociated with initial systole activity. The S2 segment is associatedwith initial diastole activity. The linking segment is associated withat least a portion of heart activity occurring between the S1 and S2segments during a systolic interval between the initial systole anddiastole activity. The controller 160 changes a value for at least oneof the pacing parameters between the cardiac cycles. The controller 160implements one or more processes described herein to determine valuesfor one or more pacing parameters that yield a desired level ofhemodynamic performance.

The controller 160 includes an analysis module 171 and a setting module173 that function in accordance with embodiments described herein. Theanalysis module 171 analyzes a characteristic of interest from the heartsounds within at least a portion of the linking segment. Thecharacteristic of interest is indicative of an “amount” of the heartsounds over at least a portion of the systolic interval between theinitial systole and diastole activity. The amount of the heart soundsmay be derived in different manners, such as determining the energycontent, intensity and the like, as well as relations there between. Thelevel of the characteristic changes as the pacing parameter is changed.The setting module 173 sets a desired value for the pacing parameterbased on the characteristic of interest from the heart sounds for atleast the portion of the linking segment. The pacing parameter mayrepresent at least one of an AV delay, a VV delay, a VA delay,intra-ventricular delays, electrode configurations and the like. Thecontroller 160 changes at least one of the AV delay, the VV delay, theVA delay, the intra-ventricular delays, electrode configurations andlike in order to reduce systolic turbulence and regurgitation.

The RF circuit 110 may be configured to handle and/or manage thebi-directional communication link between the IMD 101 and the wirelessbridge device 102. The RF circuit 110 is controlled by themicrocontroller 160 and may support a particular wireless communicationprotocol while communicating with the wireless bridge device 102, suchas Bluetooth low energy, Bluetooth, ZigBee, Medical ImplantCommunication Service (MICS), or the like. Protocol firmware may bestored in memory 194, which is accessed by the microcontroller 160. Theprotocol firmware provides the wireless protocol syntax for thecontroller 160 to assemble data packets, establish communication links104, and/or partition data received from the wireless bridge device 102.

The microcontroller 160 is coupled to memory 194 by a suitabledata/address bus 196, wherein the programmable operating parameters usedby the microcontroller 160 are stored and modified, as required, inorder to customize the operation of IMD 101 to suit the needs of aparticular patient. The memory 194 also stores data sets (raw data,summary data, histograms, etc.), such as the IEGM data, heart sounddata, pressure data, Sv02 data and the like for a desired period of time(e.g., 1 hour, 24 hours, 1 month). The memory 194 may store instructionsto direct the microcontroller 160 to analyze the cardiac signals andheart sounds identify characteristics of interest and derive values forpredetermined statistical parameters. The IEGM, pressure, and heartsound data stored in memory 194 may be selectively stored at certaintime intervals, such as 5 minutes to 1 hour periodically or surroundinga particular type of arrhythmia of other irregularity in the heartcycle. For example, the memory 194 may store data for multiplenon-consecutive 10 minute intervals.

The memory 194 may also contain a pre-defined algorithm that generates apasskey. The passkey may be used during a pairing and/or bondingprocedure between the IMD 101 and the wireless bridge device 102 toestablish the bi-directional communication link 104. The passkey may begenerated based on connection identification information. The connectionidentification information may include a dynamic seed and/or a staticidentification or encrypted static identification transmitted by the RFcircuit 110 through the bi-directional communication link 104 from thewireless bridge device 102 and inputted into the pre-defined algorithm.Optionally, the dynamic seed may be a random number generated by themicrocontroller 160, based on the local system clock of the IMD 101, orthe like that is transmitted by the RF circuit 110 to the wirelessbridge device 102. Additionally or alternatively, the staticidentification may be stored on the memory 194 representing a productserial identification number of the IMD 101, which is a unique numberassigned to the IMD 101 by a manufacturer of the IMD 101. Optionally,the static identification may be a pre-determined number stored on thememory 194 set by a user.

The pacing and other operating parameters of the IMD 101 may benon-invasively programmed into the memory 194 through the RF circuit 110via the bi-directional communication link 104. The RF circuit 110 iscontrolled by the microcontroller 160 and receives data for transmissionby a control signal 111. The RF circuit 110 allows intra-cardiacelectrograms, pressure data, acoustic data, Sv02 data, and statusinformation relating to the operation of IMD 101 (as contained in themicrocontroller 160 or memory 194) to be sent to the wireless bridgedevice 102 through the established bi-directional communication link104. The RF circuit 110 also allows new pacing parameters for thesetting module 173 used by the IMD 101 to be programmed through thebi-directional communication link 104.

To establish the bi-directional communication link 104 between thewireless bridge device 102 and the IMD 101, the microcontroller 160 mayenter an advertisement mode by instructing the RF circuit 110 totransmit or broadcast one or more advertisement notices along adedicated advertisement channel defined by the wireless protocol. Theadvertisement channel is a point to multipoint, unidirectional, channelto carry a repeating pattern of system information messages such asnetwork identification, allowable RF channels to establish thebi-directional communication link 104, and/or the like that is includedwithin the advertisement notice. The advertisement notice may berepeatedly transmitted after a set duration or an advertisement perioduntil the bi-directional communication link 104 is established with thewireless bridge device 102.

Optionally, the length of the advertisement period may be adjusted bythe microcontroller 160 during a select advertisement mode. For example,during the select advertisement mode the microcontroller 160 may reducethe length of the advertisement period relative to not being in theselect advertisement mode. The reduced length of the advertisementperiod results in the RF circuit 110 transmitting more or an increasednumber of advertisement notices relative to not being in the selectadvertisement mode.

The IMD 101 may also include a physiologic sensor 112, such as anaccelerometer commonly referred to as a “rate-responsive” sensor becauseit is typically used to record the activity level of the patient oradjust pacing stimulation rate according to the exercise state of thepatient. Optionally, the physiological sensor 112 may further be used todetect changes in cardiac output, changes in the physiological conditionof the heart, or changes in activity (e.g., detecting sleep and wakestates) and movement positions of the patient. While shown as beingincluded within IMD 101, it is to be understood that the physiologicsensor 112 may also be external to the IMD 101, yet still be implantedwithin or carried by the patient. A common type of rate responsivesensor is an activity sensor incorporating an accelerometer or apiezoelectric crystal, which is mounted within the housing 138 of theIMD 101.

The physiologic sensor 112 may be used as the acoustic sensor that isconfigured to detect the heart sounds. For example, the physiologicsensor 112 may be an accelerometer that is operated to detect acousticwaves produced by blood turbulence and vibration of the cardiacstructures within the heart (e.g., valve movement, contraction andrelaxation of chamber walls and the like). When the physiologic sensor112 operates as the acoustic sensor, it may supplement or replaceentirely acoustic sensors. Other types of physiologic sensors are alsoknown, for example, sensors that sense the oxygen content of blood,respiration rate and/or minute ventilation, pH of blood, ventriculargradient, etc. However, any sensor may be used which is capable ofsensing a physiological parameter that corresponds to the exercise stateof the patient and, in particular, is capable of detecting arousal fromsleep or other movement.

The IMD 101 additionally includes a battery 113, which providesoperating power to all of the circuits shown. The IMD 101 is shown ashaving impedance measuring circuit 115 which is enabled by themicrocontroller 160 via a control signal 114. Herein, impedance isprimarily detected for use in evaluating ventricular end diastolicvolume (EDV) but is also used to track respiration cycles. Other usesfor an impedance measuring circuit include, but are not limited to, leadimpedance surveillance during the acute and chronic phases for properlead positioning or dislodgement; detecting operable electrodes andautomatically switching to an operable pair if dislodgement occurs;measuring respiration or minute ventilation; measuring thoracicimpedance for determining shock thresholds; detecting when the devicehas been implanted; measuring stroke volume; and detecting the openingof heart valves, etc. The impedance measuring circuit 115 isadvantageously coupled to the switch 174 so that impedance at anydesired electrode may be obtained.

FIG. 3 illustrates a functional block diagram of the external device 201that is operated in accordance with the processes described herein andto interface with the wireless bridge device 102 and/or the IMD 101 asdescribed herein. The external device 201 may be a workstation, aportable computer, a tablet computer, an IMD programmer, a PDA, a cellphone and/or the like located within a home of the patient 106, ahospital or clinic, an automobile, at an office of the patient, or thelike.

The external device 201 may include an internal bus 301 that mayconnect/interface with a Central Processing Unit (“CPU”) 302, ROM 304,RAM 306, a hard drive 308, a speaker 310, a printer 312, a CD-ROM drive314, a floppy drive 316, a parallel I/O circuit 318, a serial I/Ocircuit 320, the display 322, a touchscreen 324, a standard keyboard326, custom keys 328, and an RF subsystem 330. The internal bus 301 isan address/data bus that transfers information between the variouscomponents described herein. The hard drive 308 may store operationalprograms as well as data, such as stimulation waveform templates anddetection thresholds.

The CPU 302 typically includes a microprocessor, a microcontroller, orequivalent control circuitry, designed specifically to controlinterfacing with the external device 201 and with the wireless bridgedevice 102 and/or the IMD 101. The CPU 302 may include RAM or ROMmemory, logic and timing circuitry, state machine circuitry, and I/Ocircuitry to interface with the wireless bridge device 102 and/or theIMD 101. The display 322 (e.g., may be connected to the video display332). The display 322 displays various information related to theprocesses described herein. The touchscreen 324 may display graphicinformation relating to the IMD 101 and include a graphical userinterface. The graphical user interface may include graphical icons,scroll bars, buttons, and the like which may receive or detect user ortouch inputs 334 for the external device 201 when selections are made bythe user. Optionally the touchscreen 324 may be integrated with thedisplay 322. The keyboard 326 (e.g., a typewriter keyboard 336) allowsthe user to enter data to the displayed fields, as well as interfacewith the RF subsystem 330. Furthermore, custom keys 328 turn on/off 338(e.g., EVVI) the external device 201. The printer 312 prints copies ofreports 340 for a physician to review or to be placed in a patient file,and the speaker 310 provides an audible warning (e.g., sounds and tones342) to the user. The parallel I/O circuit 318 interfaces with aparallel port 344. The serial I/O circuit 320 interfaces with a serialport 346. The floppy drive 316 accepts diskettes 348. Optionally, theserial I/O port may be coupled to a USB port or other interface capableof communicating with a USB device such as a memory stick. The CD-ROMdrive 314 accepts CD ROMs 350.

The RF subsystem 330 includes a central processing unit (CPU) 352 inelectrical communication with an RF circuit 354, which may communicatewith both memory 356 and an analog out circuit 358. The analog outcircuit 358 includes communication circuits to communicate with analogoutputs 364. The external device 201 may wirelessly communicate with thewireless bridge device 102 and utilize protocols, such as Bluetooth,Bluetooth low energy, ZigBee, MICS, and the like.

FIGS. 4A-B illustrates a functional block diagram of the wireless bridgedevice 102. It should be noted that the wireless bridge device 102 isfor illustration purposes only, and it is understood that the circuitryand/or components may be duplicated, eliminated or disabled in anydesired combination thereof.

In the illustrated embodiment shown in FIGS. 4A-B, the wireless bridgedevice 102 may include a housing 402 that encloses an antenna 412, abattery 418 or power source, and a system on chip (SoC) 404. The housing402 may be comprised of a plastic and/or other non-conductive material.The housing 402 may be configured to be handheld by the user and/orconfigured to be placed against an exterior surface of the patient 106(e.g., the skin of the patient). The battery 418 provides operatingpower to the SoC 404. Optionally, the antenna 412 may be positioned onthe exterior surface of the housing 402.

The SoC 404 may include a memory module 408, an input/output (I/O)interface 414, a processor circuit 406, analog circuitry 410, and an RFcircuit 420. Optionally, the SoC 404 may be a Bluetooth Low EnergySystem on Chip. For example, the RF circuit 420, the memory module 408,and the processor circuit 406 may be designed for operating under theBLE wireless protocol.

The SoC 404 may be an integrated circuit (IC) such that all componentsof the SoC 404 are on a single chip substrate (e.g., a single silicondie, a chip). For example, the SoC 404 may have the memory module 408,the I/O interface 414, the processor circuit 406, and the analogcircuitry 410 embedded on a single die contained within a single chippackage (e.g., QFN, TQFP, SOIC, BGA, and/or the like).

Additionally or alternatively, the SoC 404 may comprise a plurality ofchips (e.g., silicon dies, ICs) stacked within a single chip package.For example, the analog circuitry 410 and the processor circuit 406 aretwo different ICs. The ICs are stacked vertically on a substrate withina single chip package. Each IC is internally connected to each otherand/or bonded by wire to the single chip package.

Additionally or alternatively, the SoC 404 may represent a plurality ofdiscrete integrated circuit packages (e.g., the memory module 408, theI/O interface for 414, the analog circuitry 410, the RF circuit 420)stacked vertically to reduce PCB area. For example, the analog circuitry410 and the processor circuit 406 may each be in a ball grid array (BGA)package, respectively, which has interconnection pins along the bottomsurface of each BGA package. The BGA package of the analog circuitry 410is coupled to a printed circuit board (PCB) of the wireless bridgedevice 102, and has an extended substrate around the BGA package. TheBGA package of the processors circuit 406 is vertically stacked atop ofthe BGA package of the analog circuitry 410 having the interconnectionpins of the processors circuit 406 coupled to the extended substrate.Thereby, the only PCB footprint is the BGA package of the analogcircuitry 410.

The analog circuitry 410 may include amplifiers, filters, analog todigital converters, memory storage devices, digital signal processorsand/or the like. Optionally, the analog circuitry 410 may be integratedwith the RF circuit 420.

The memory module 408 may include EEPROM, RAM, ROM, flash, and/or a harddrive. The memory module 408 may include protocol firmware that may beaccessed by the processor circuit 406. The protocol firmware may providethe wireless protocol syntax for the processor circuit 406 to assemblerdata packets, establish the bi-directional communication links 104 and105 based on the wireless protocol, partition data from the datapackets, and/or the like. The protocol syntax may include specificationson the structure of packets (e.g., frame size, packet specifications,appropriate number of bits, frequency, and/or the like) such asadvertisement notices or data packets that are received and/ortransmitted by the wireless bridge device 102.

The protocol syntax may further include a time slice algorithm. The timeslice algorithm may subdivide a communication interval (e.g., similar tothe connection event, the communication interval 732 of FIG. 7) into oneor more time slices when the wireless bridge device 102 has concurrentand/or simultaneous bi-directional communication links 104 and 105.During the communication interval the external device 201 and thewireless bridge device 102 exchange data packets along thebi-directional communication link 105. A length of the communicationinterval may be defined by the wireless protocol and/or the externaldevice 102 corresponding to a length of time for the wireless bridgedevice 102 to respond to a data packet transmitted from the externaldevice 201. Additionally or alternatively, if the external device 201does not receive a data packet from the wireless bridge device 102during the communication interval, the external device 201 may terminateand/or close down the bi-directional communication link 105.

During the communication interval, while the wireless bridge device 102has concurrent and/or simultaneous bi-directional communication links104 and 105, the wireless bridge device 102 and the IMD 101 may exchangedata packets along the bi-directional communication link 104. Theexchange of data packets between the wireless bridge device 102 and theIMD 101 occurs prior to the wireless bridge device 102 transmits a datapacket (e.g., completing the exchange) to the external device 201. Forexample, the external device 201 transmits a first data packet to thewireless bridge device 102. The wireless bridge device 102 relays (e.g.,transmits) the first data packet to the IMD 101. The IMD 101 receivesthe first data packet and transmits a response data packet to thewireless bridge device 102. The wireless bridge device 102 receives theresponse data packet and relays (e.g., transmits) the response data tothe external device 201, within the communication interval.

The time slices correspond to when transmission data packets from thewireless bridge device 102 may be transmitted over the bi-directionalcommunication links 104 and/or 105, received by the wireless bridgedevice 102, and/or the like. The time slices enable the exchanges ofdata packets between the wireless bridge device 102, the IMD 101, andthe external device 201 to be within the communication intervalmaintaining the bi-directional communication links 104 and 105concurrently and/or simultaneously. For example, a first time slice maycorrespond to when the wireless bridge device 102 can relay (e.g.,transmit) a data pack received by the external device 201 to the IMD101, a second time slice may correspond to when the wireless bridgedevice 102 may receive a response data packet from the IMD 101, and athird time slice may correspond to when the wireless bridge device mayrelay (e.g., transmit) the response data packet to the external device201. It should be noted that in various embodiments the communicationinterval may be subdivided equally such that the time slices haveapproximately the same or equal lengths.

Additionally or alternatively, at least two of the time slices may havedifferent lengths. For example, a time slice corresponding to thetransmission of a data packet from the wireless bridge device 102 to theIMD 101 may be larger relative to the time slices correspondingtransmissions of data packets from the IMD 101 to the wireless bridgedevice 102 and from the wireless bridge device 102 to the externaldevice 201. In another example, a time slices corresponding to thetransmission of data packets from the IMD 101 to the wireless bridgedevice 102 and from the wireless bridge device 102 to the externaldevice 201 may be larger relative to the time slice corresponding to thetransmission of a data packet from the wireless bridge device 102 to theIMD 101.

A length of the time slices may be based on the length of thecommunication interval, a size of the data packet received by thewireless bridge 102 from the external device, and/or the like. Forexample, time slices may be longer when subdivided from communicationintervals having a longer length relative to a shorter communicationinterval.

Optionally, one of the time slices may correspond to a secondcommunication interval (e.g., 748 of FIG. 7). For example, the secondcommunication interval may be defined by the wireless bridge device 102corresponding to a length of time for the IMD 101 to respond to a datapacket transmitted from the wireless bridge device 102. The secondcommunication interval may be within the communication interval betweenthe wireless bridge device 102 and the external device 201.

Returning to FIGS. 4A and 4B, the RF circuit 420 of the wireless bridgedevice 102 may include a transceiver or transmitter-receiver thatincludes an oscillator, a modulator, a demodulator, one or moreamplifiers, an impedance circuit, and/or the like. The RF circuit 420allows the wireless bridge device 102 to facilitate telemetry toestablish one or more bi-directional communication links 104, 105 usingthe wireless communication protocol such as BLE, Bluetooth, ZigBee, orthe like via the antenna 412.

The antenna 412 may be an omnidirectional antenna such that the antenna412 radiates and/or receives RF electromagnetic fields uniformly orequally in all directions. Thereby, the antenna 412 may transmit and/orreceive wireless communications equally without limiting a position ofthe wireless bridge device 102 with respect to the external device 201and/or the IMD 101. The antenna 412 may be tuned to a predeterminedresonant frequency such that the antenna 412 has a signal performanceexhibiting a lower return loss at a predetermined resonant frequencyrelative to alternative frequencies, such as a resonant frequency of thewireless protocol. For example, the wireless protocol may correspond tothe BLE protocol that operates in a 2.4 GHz band. The antenna 412 may beconfigured from a shape of the antenna 412 (e.g., length,cross-sectional thickness, area) and/or by coupling components to theantenna 412 (e.g., capacitor, inductor) to achieve the resonantfrequency of 2.4 GHz.

Optionally, the wireless bridge device 102 may include additionalantennas. For example, the wireless bridge device 102 may include adirectional antenna (not shown) configured for the bi-directionalcommunication link 104 with the IMD 101 while the antenna 412 may be forthe bi-directional communication link 105 with the external device 201.The directional antenna may be configured to radiate and/or receive moreRF electromagnetic fields in one or more directions relative to otherdirections.

For example, the IMD 101 may be embedded within the chest of the patient106. As shown in FIG. 4B, the housing 402 of the wireless bridge device102 may include a flat surface 422 area along a horizontal plane. Theflat surface 422 may allow the wireless bridge device 102 to bepositioned on a chest of the patient 106 such that the flat surface 422and the chest of the patient 106 are in contact. The position of thewireless bridge device 102 on the chest of the patient 106 allows thewireless bridge device 102 to be positioned proximate to the IMD 101.The directional antenna may be configured to direct and/or receive RFelectromagnetic fields along a directional vector that extendsperpendicular from the surface area of the flat surface 422 towards thechest of the patient 106. Thereby, the directional antenna may radiateand receive more RF electromagnetic fields towards/from the chest,including the direction of the IMD 101, relative to other directionsalong the surface area of the housing 402.

As depicted in FIG. 4A, the I/O interface 414 may be an interconnect orbus that electrically couples the memory module 408, the analogcircuitry 410, and the processor circuit 406 with each other. The I/Ointerface 414 enables data and/or instructions to be delivered and/orreceived between the processor circuit 406, the memory module 408, andthe analog circuitry 410. Additionally or alternatively, the I/Ointerface 414 may electrically couple the SoC 404 with peripheralcomponents of the SoC 404 such as the antenna 412, the battery 418, anda user interface component 416.

The processor circuit 406 may include one or more processors ormicroprocessors, or equivalent control circuitry, designed forcontrolling the components of the wireless bridge device 102. Optionallythe processor circuit 406 may include EEPROM, RAM or ROM memory, logicand timing circuitry, state machine circuitry, and I/O circuitry. Theprocessor circuit 406 may process and/or monitor input signals (data)received via the I/O interface 414 as controlled by executing programcode stored on the memory included within the processor circuit 406and/or the memory module 408.

Additionally or alternatively, the housing 402 may include a userinterface component 416, such as a button, a tactile switch, or the likeon the housing 402, such as shown in FIG. 4B. The user interfacecomponent 416 may be configured to activate and/or de-activate thewireless bridge device 102. For example, when the wireless bridge device102 is positioned proximately to the IMD 101, such as on the chest ofthe patient 106, a user may turn on the wireless bridge device 102 usingthe user interface component 416.

FIGS. 5 and 8 illustrate flowcharts of methods 500 and 800 for bridginga bi-directional communication link between an external device (e.g.,201) and an implantable medical device (IMD) (e.g., 101). The methods500 and 800 may be implemented as a software algorithm, package, orsystem that directs one or more hardware circuits or circuitry toperform the actions described herein. For example, the operations of themethods 500 and 800 may represent actions to be performed by one or morecircuits that include or are connected with processors, microprocessors,controllers, microcontrollers, Application Specific Integrated Circuits(ASICs), Field-Programmable Gate Arrays (FPGAs), or other logic-baseddevices that operate using instructions stored on a tangible andnon-transitory computer readable medium (e.g., a computer hard drive,ROM, RAM, EEPROM, flash drive, or the like), such as software, and/orthat operate based on instructions that are hardwired into the logic ofthe.

At least one technical effect of at least one portion of the methodsdescribed herein includes i) establishing a first bi-directionalcommunication link between an external device and a wireless bridgedevice according to a wireless protocol, ii) establishing a secondbi-directional communication link between the wireless bridge device andan IMD concurrently with the first bi-directional communication linkaccording to the wireless protocol, iii) receiving a data packet fromthe external device at the wireless bridge device, and/or iv)transmitting the data packet from the wireless bridge device to the IMDduring a communication interval.

Beginning at 501, the wireless bridge device 102 is positioned proximateto the IMD 101. For example the wireless bridge device 102 may bepositioned against an exterior surface of the patient 106, such as theskin of the patient 106, approximate to a position of the IMD 101 withrespect to the patient. Additionally or alternatively, the patient 106may be moved such that a positioned of the wireless bridge device 102 isproximate to the IMD 101. For example, the wireless bridge device 102may be mounted and/or stationary, such as mounted to a bed of thepatient 106, within a patient monitoring system, and/or the like. Thepatient 106 may be moved to a location proximate to the wireless bridgedevice 102 (e.g., seated and/or lying on the bed) to position thewireless bridge device 102 proximate to the IMD 101.

At 502, a first bi-directional communication link (e.g., thebi-directional communication link 105) is established between theexternal device 201 and the wireless bridge device 102 according to thewireless protocol.

For example, a user and/or patient may activate the wireless bridgedevice 201 using the user interface component 416. When activated, theSoC 404 may enter a powered state. During the powered state, the battery418 may provide electric current and/or voltage potential to the SoC 404enabling the wireless bridge device 201 to establish one or morebi-directional communication links by entering an advertisement mode.During the advertisement mode the wireless bridge device 201 broadcastsone or more advertisement notices 605 along a dedicated advertisementchannel defined by the wireless protocol.

FIG. 6 illustrates a timing diagram 600 to establish the bi-directionalcommunication link 105 between the wireless bridge device 102 and theexternal device 201, according to an embodiment of the presentdisclosure. The wireless bridge device 102 and the external device 201use a wireless protocol (e.g., BLE) that utilizes a dedicated frequencyand/or frequency channels for one or more advertisement channels. Thewireless bridge device 102 transmits an advertisement notice 605 alongone or more of the advertisement channels using the RF circuit 420.

The advertisement notice 605 represents a data packet that may containfrequency synchronization information utilized to form thebi-directional communication link 105, address information of thewireless bridge device 102, address information of the external device201, and/or the like as defined by the wireless protocol. Additionallyor alternatively, the advertisement notice 605 may include pairingand/or bondable information (e.g., passkey seed information). Theadvertisement notice 605 may be repeated, at a set or variable intervalor an advertisement period 602, until the bi-directional communicationlink 105 is established. The advertisement period 602 represents alength of time between advertisement notices 605 transmitted by thewireless bridge device 102.

For example, the advertisement period 602 may be 5 seconds such that theadvertisement notice 605 may be repeated every 5 seconds. Optionally,the advertisement period 602 may be longer or shorter than the aboveexample. The advertisement period may be predetermined and stored in thememory module 408. Optionally, the advertisement period 602 may be inputby a user (e.g., physician or clinician using the user interfacecomponent 416).

The external device 201 monitors the one or more advertisement channelsduring a scanning interval 603 to detect one or more of theadvertisement notices 605. The scanning interval 603 may be initiated bythe user. For example, the user, using the touchscreen 324 or standardkeyboard 336, may instruct the external device 201 to establish thebi-directional communication link 105. The CPU 302 (FIG. 3) of theexternal device 201 instructs the RF subsystem 330 to monitor one ormore advertisement channels, for example, every 1 s corresponding to thescanning interval 603. The RF subsystem repeats the scanning interval603 every scan period 601 such that the scanning interval 603 may berepeated, for example, every 4 s. For example, the scan period 601represents a length of time between scan intervals. The scanninginterval 603 and/or scan period 601 may be longer or shorter than theabove example. Additionally or alternatively, the scanning interval 603and/or scan period 601 may be a predetermined length stored on the ROM304, the RAM 306, or the hard drive 308. Optionally, the scanninginterval 603 and/or scan period 601 may be configured by the user, suchthat, the scanning interval 603 or period 601 may be increased ordecreased based on a user input received by the touchscreen 324 orstandard keyboard 603. The RF subsystem 330 may continually repeat thescanning interval 603 until the CPU 302 acknowledges receipt of theadvertisement notice 605.

The scan period 601 and the advertisement period 602 occur independentand asynchronous with respect to one another, such that theadvertisement notices 605 intermittently overlap the scan intervals 603at 604 and 606. Each period length is predetermined from distinct andseparate sources. The scan period 601 is predetermined or configure bythe user of the external device 201. Separately, the advertisementperiod 602 is predetermined by the protocol syntax stored in the memory408. For example, one of the scan period 601 or the advertisement period602 may be altered, while, the length of the other period (e.g.,advertisement period 602, scan period 601) remains constant.

The scan period 601 has an asynchronous phased relation with respect tothe advertisement period 602 in order that a phase interval 615 betweenbeginnings of the scanning intervals 603 and advertisement notices 605continuously (or intermittently) changes. For example, the scan period601 may be 4 s having the scanning interval 603 of 1 s, and theadvertisement period 602 may be 5 s having the advertisement notice 605of 1.5 s. The different lengths of the periods 601 and 602 represent theasynchronous phased relationship with respect to each other. Theasynchronous phased relationship causes the advertisement notice 605 andthe scanning interval 603 to begin at different times thus creatingphase intervals 615. The length of the phase interval 615 can beextended and/or shortened by changing the advertisement period 602 ofthe wireless bridge device 102 or the scan period 601 of the externaldevice 201. Thus, by configuring the advertisement period 602 or thescan period 601, the phase interval 615 may continuously change or bechanged intermittently after a set number of cycles. The beginning ofthe cycle occurs at the transmission of the advertisement notice 605 orthe scan interval 603. The phase interval 615 may be controlled by theuser changing the scan period 603 of the external device 201 or by theprocessor circuit 406 changing the advertisement period 602 of thewireless bridge device 102.

For example, the phase interval 615 of the timing diagram 600, iscontinuously changing after each cycle. The phase interval 615 a,measured between the beginning of the advertisement notice 605 a and thebeginning of the scan interval 603 a, may be approximately 1.5 s. Theadvertisement notice 605 a and the scanning interval 603 a do notpartially or wholly overlap. The phase interval 615 b, between theadvertisement notice 605 b and the scanning interval 603 b, may beapproximately 750 ms. The phase interval 615 c, between theadvertisement notice 605 c and the scanning interval 603 c, may beapproximately 250 ms. Accordingly, the length of the phase interval 615continuously changes each cycle. The changes in the length of the phaseinterval 615 cooperate such that each cycle or repetition of thescanning interval 603 and the advertisement notice 605 shifts withrespect to each other, thereby allowing for partially overlapping eventsat 604 and 606 to occur. For instance, only the phase intervals 615b-615 c are associated with partially overlapping advertisement notices605 b-c and scanning intervals 615 b-c. Although the periods 601, 602are asynchronous, the scanning intervals 603 and the advertisementnotices 605 will partially overlap and enable the external device 201intermittently or after a set number of cycles to receive theadvertisement notice 605. The overlaps occur intermittently, in thatafter a number of cycles the scanning interval 603 and advertisementnotice 605 will partially overlap in fewer cycles than the number ofcycles. For example, the scanning interval 603 and advertisement notice605 partially overlap after the fourth and fifth cycle of the scanninginterval 603 or the third and fourth cycle of the advertisement notice605.

Optionally, the wireless bridge device 102 may have a selectadvertisement mode that decreases the number of cycles needed until thebi-directional communication link 105 is established, by increasing thelikelihood of the scanning interval 603 partially overlapping theadvertisement notice 605. For example, the select advertisement mode maybe activated by the user using the user interface component 416. Whenthe select advertisement mode is activated, the processor circuit 406may decrease the length of the advertisement period 602, relative to notbeing in the select advertisement mode, thereby, increasing the numberof advertisement notices 605 in a time frame 609. The increased numberof advertisement notices 605 increase the number of partial overlapswith the scanning intervals 603, allowing the external device 201 todetect or receive the advertisement notice 605 in a shorter amount ofcycles relative to the wireless bridge device 102 not in the selectadvertisement mode.

Optionally, the wireless bridge device 102 may be programmed and/orconfigured to disable the RF circuit 420 and/or end or terminate thepowered state when a connection request is not received within apredetermined period. The predetermined period may be stored on thememory module 408, defined by the wireless protocol. For example, thewireless bridge device 102 may stop transmitting advertisement notices605 after the predetermined period, such as five minutes. It should benoted that in other embodiments the predetermined period may be greaterthan or lesser than five minutes.

Once the external device 201 receives the advertisement notice 605, inthe form of a data packet transmitted from the wireless bridge device102, the CPU 302 analyzes or compares the data packet with the protocolsyntax stored on the ROM 304, the RAM 306, or the hard drive 308. Theprotocol syntax may include the structure of the advertisement notice(e.g., data packet specifications, appropriate number of bits,frequency, or the like) utilized by the wireless protocol. Optionally,the advertisement notice 605 may include a unique code designating thepacket as an advertisement. By comparing the protocol syntax with thedata packet, the CPU 302 determines whether the received data packet isan advertisement notice 605 using the wireless protocol of the externaldevice 201. If the received data packet is determined not to be anadvertisement notice, the external device 201 may continue scanning theadvertisement channel. When the CPU 302 determines that the data packetreceived by the RF circuit 354 is the advertisement notice 605 (havingthe proper syntax), the CPU 302 outputs a connection request (e.g.,within a payload of a data packet) to be transmitted by the RF circuit354 along the advertisement channel.

The CPU 302 constructs a data packet representing the connection requestby adding packet frames to conform to the wireless protocol such as theaddress of the wireless bridge device 102 and/or external device 201,error detection codes such as CRC, a payload, or the like. The payloadmay include connection instructions (e.g., frequency of the data channelfor the bi-directional communication link 105) from the user intendedfor the wireless bridge device 102. When the data packet has beenformed, the CPU 302 outputs the data packet to the RF subsystem 330 tobe transmitted along the advertisement channel that was to the wirelessbridge device 102 of the advertisement notice 605. Optionally, the datapacket may include connection identification information (e.g., a staticidentification) corresponding to the IMD 101 to establish thebi-direction communication link 104 as further described below.

The RF circuit 420 receives the data packet from the RF signal receivedby the antenna 412 via the I/O interface 414. The RF circuit 420 maydemodulate the RF signal and output the data packet to the processorcircuit 406 via the I/O interface 414. The processor circuit 406 maystore the data packet in the memory module 408 for analysis. Theprocessor circuit 406 determines whether the data packet is in responseto the advertisement notice 605 by comparing the address information ofthe data packet with the address transmitted by the wireless bridgedevice 102 within the advertisement notice 605. If the addressinformation matches, the processor circuit 406 partitions the payloadfrom the data packet and carries out the instruction of the connectionrequest from the payload by comparing the instructions to a storedinstruction set on the memory module 408 for the wireless protocol.Optionally, the processor circuit 406 may compare the addressinformation of the external device 201 on the data packet with apermissible links table stored in the memory module 408 to determinewhether the wireless bridge device 102 should ignore or partition thepayload of the data packet. Once the processor circuit 406 identifiesthe connection request, the processor circuit 406 may instruct the RFcircuit 420 to monitor the data channel identified in the connectionrequest for further instructions from the external device 201, therebyestablishing the bi-directional communication link 105.

FIG. 7 illustrates a timing diagram 700 between the external device 201,the wireless bridge device 102, and the IMD 101, according to anembodiment of the present disclosure. The timing diagram 700 may besubdivided into subsections (e.g., 720, 730, 740) corresponding tostages of a bi-directional communication link between the externaldevice 201 and the IMD 101 via the wireless bridge device 102. Thesubsection 720 corresponds to forming the bi-directional communicationlink 105, as further described in connection with FIG. 6.

The subsection 730 correspond to a series of data packets 710 and 712being transmitted from the external device 201 and the wireless bridgedevice 102 over the bi-directional communication link 105. For example,the external device 201 transmits the data packet 710 a along thebi-directional communication link 105. The wireless bridge device 102receives the data packet 710 a and in response transmits the data packet712 a.

Additionally or alternatively, when the bi-directional communicationlink 105 is established, the bi-directional communication link 105 maybe configured to have the external device 201 in a master configurationand the wireless bridge device 102 in a slave configuration as definedby the wireless protocol. While in the master configuration, theexternal device 201 may have unidirectional control over one or moreother devices, such as the wireless bridge device 102. For example, theexternal device 201 may define a communication interval 732 within thedata packet corresponding to the connection request.

The communication interval 732 corresponds to a length of time for thewireless bridge device 102 to respond to a data packet transmitted fromthe external device 201. The communication interval 732 is defined froman anchor point 734. The anchor point 734 is based on when the externaldevice 201 starts to transmit a data packet 742 a to the wireless bridgedevice 102.

Additional examples of forming a bi-directional communication links isdisclosed in U.S. patent application Ser. No. 14/091,809, entitled,“SYSTEM AND METHODS FOR ESTABLISHING A COMMUNICATION SESSION BETWEEN ANIMPLANTABLE MEDICAL DEVICE AND AN EXTERNAL DEVICE,” which is expresslyincorporated herein by reference.

Returning to FIG. 5, at 504 a second bi-directional communication link(e.g., the bi-directional communication link 104) is established betweenthe wireless bridge device 102 and the IMD 101 concurrently with thefirst bi-directional communication link (e.g., the bi-directionalcommunication link 105) according to the wireless protocol.

For example, similar to the process described in connection with FIG. 6,the IMD 101 may be configured to enter an advertisement mode. During theadvertisement mode, the IMD 101 may broadcast one or more advertisementnotices 705 along a dedicated advertisement channel defined by thewireless protocol (e.g., BLE).

The wireless bridge device 102 may receive instructions from theexternal device 201 corresponding to a data packet 710 b. The receivedinstructions may instruct the wireless bridge device 102 to monitor oneor more of the dedicated advertisement channels during a scan interval714 (e.g., similar to the scan intervals 603) for one or more of theadvertisement notices 705 transmitted by the IMD 101 to establish thebi-directional communication link 104.

The wireless bridge device 102 may detect at least one of the one ormore advertisement notices 705, and establish the bi-directionalcommunication link 104 based on the at least one of the one or moreadvertisement notices 705. For example, the wireless bridge device 102receives the advertisement notice 705, in the form of a data packettransmitted from the IMD 101, the processor circuit 406 may analyze orcompare the data packet with the protocol syntax stored on the memorymodule 408. By comparing the protocol syntax with the data packet, theprocessor circuit 406 determines whether the received data packet is anadvertisement notice 705 using the wireless protocol of the IMD 101. Ifthe received data packet is determined not to be an advertisement noticefrom the IMD 101, the wireless bridge device 102 may continue scanningthe advertisement channel. When the processor circuit 406 determinesthat the data packet received by the RF circuit 420 is the advertisementnotice 705 (having the proper syntax), the processor circuit 406 outputsa connection request (e.g., within a payload of a data packet) to betransmitted by the RF circuit 354 along the advertisement channel.

Optionally, the data packet 710 b from the external device 201 mayinclude connection identification information of the IMD 101. Theconnection identification information may correspond to the IMD 101 andis used by the wireless bridge device 102 to establish thebi-directional communication link 104. For example the connectionidentification information may correspond to a product serialidentification number of the IMD 101, which is a unique number assignedto the IMD 101 by a manufacturer of the IMD 101. The connectionidentification information may be received by the user from thetouchscreen 324 or standard keyboard 336. The connection identificationinformation may be used by the wireless bridge device 102 to verify theadvertisement notice 705.

For example, the wireless bridge device 102 stores the connectionidentification information on to the memory module 408 corresponding toa product serial identification number of the IMD 101. The advertisementnotice 705 of the IMD 101 may correspond to a data packet with multipleframes defined by the wireless protocol. One of the frames may be anadvertising payload which includes the product serial identificationnumber to identify the IMD 101. When the wireless bridge device 102receives the advertisement notice 705 and determines that theadvertisement notice 705 conforms to the protocol syntax, the processorcircuit 406 may partition the advertisement payload from theadvertisement notice 705. The processor circuit 406 may compare theidentification number stored within the advertisement payload with theproduct serial identification number stored on the memory module 408received from the external device 201. If the advertiser payload isdetermined not to match the product serial identification number storedon the memory module 408, the wireless bridge device 102 may continuescanning the advertisement channel (e.g., perform another scan interval714). When the processor circuit 406 determines that the advertisementpayload matches the product serial identification number stored on thememory 408, the processor circuit 406 may output a connection request tobe transmitted by the RF circuit 420 along the advertisement channel.

Similarly as described above, the processor circuit 406 constructs adata packet representing the connection request by adding packet framesto conform to the protocol such as the address of the IMD 101 and/or thewireless bridge device 102, error detection codes such as CRC, apayload, or the like. The payload may include connection instructions(e.g., frequency of the data channel for the bi-directionalcommunication link 104). When the data packet has been formed, theprocessor circuit 406 outputs the data packet to the RF circuit 420 tobe transmitted along the advertisement channel that was to the IMD 101corresponding to the advertisement notice 705. Optionally, the datapacket may include identification information corresponding to theexternal device 201 of the bi-direction communication link 105.

The RF circuit 110 receives the data packet and outputs to themicrocontroller 160. The microcontroller 160 may store the data packetin memory 194 for analysis. The microcontroller 160 determines whetherthe data packet is in response to the advertisement notice 705 bycomparing the address information of the data packet with the addresstransmitted by the IMD 101 within the advertisement notice 705. If theaddress information matches, the microcontroller 160 partitions thepayload from the data packet and carries out the instruction of theconnection request from the payload by comparing the instructions to astored instruction set stored on the memory 194 relating to the wirelessprotocol. Optionally, the microcontroller 160 may compare the addressinformation of the wireless bridge device 102 and/or the external device201 on the data packet with a permissible links table stored on memory194 to determine whether the IMD 101 should ignore or partition thepayload of the data packet. Once the microcontroller 150 identifies theconnection request, the microcontroller 160 may instruct the RF circuit110 to monitor the data channel identified in the connection request forfurther instructions from the wireless bridge device 102, therebyestablishing the bi-directional communication link 104.

Additionally or alternatively, when the bi-directional communicationlink 104 is established, the bi-directional communication link 104 maybe configured to have the wireless bridge device 102 in a masterconfiguration and the IMD 101 in a slave configuration as defined by thewireless protocol.

While in the master configuration, the wireless bridge device 102 mayhave unidirectional control over one or more other devices, such as theIMD 101. For example, the wireless bridge device 102 may define acommunication interval 748 within the data packet corresponding to theconnection request. The communication interval 748 corresponds to alength of time from an anchor point that the wireless bridge device 102will receive a data packet from the IMD 101 over the data channel of thebi-directional communication link 104. Optionally, the communicationinterval 748 may correspond to a time slice within the communicationinterval 732.

Data passed through the bi-directional communication links 104 and 105are time sliced with respect to the communication interval 732. Forexample, the subsection 740 of the timeline correspond to a series ofdata packets 742, 746, and 744 being transmitted from the externaldevice 201, the wireless bridge device 102, and the IMD over thebi-directional communication links 104 and 105. The series of datapackets 742 from the external device 201 may correspond to measurementrequests, programming instructions, status updates, and/or the like forthe IMD 101. The series of data packets 744 from the IMD 101 maycorrespond to programmed responses based on the data packets 742 (e.g.,measurement requests, programming instructions, status updates). Theseries of data packets 746 from the wireless bridge device 102 may bere-transmissions of the data packets received from the external device201 and/or the IMD 101 to the IMD 101 and/or external device 201,respectively.

The communication interval 732 may be subdivided into time slices. Thetime slices may correspond to when transmission data packets from thewireless bridge device 102 are transmitted over the bi-directionalcommunication links 104 and/or 105, received by the wireless bridgedevice 102, and/or the like. The time slices enable the exchanges ofdata packets between the wireless bridge device 102, the IMD 101, andthe external device 201 to be within the communication intervalmaintaining the bi-directional communication links 104 and 105concurrently and/or simultaneously. Optionally, one of the time slicesmay correspond to the communication interval 748, allowing transmissionsof the series of data packets 744 and 746 to occur within thecommunication interval 732.

For example, the external device 201 may define the communicationinterval 732 as 100 ms as a part of the connection request forestablishing the bi-directional communication link 105. The wirelessbridge device 102 may define the communication interval 748 as 50 ms asa part of the connection request for establishing the bi-directionalcommunication link 104. The external device 201 transmits the datapacket 742 a to the wireless bridge device 102 over the bi-directionalcommunication link 105. As described above, the data packet 742 a maycorrespond to the anchor point 734 defining a start of the communicationinterval 732. The RF circuit 420 receives and outputs the data packet742 a to the processor circuit 406. The processor circuit 406 maypartition and replace the address information of the data packet 742 acorresponding to the wireless bridge device 102 with the addressinformation of the IMD 101, thereby constructing the data packet 746 a.It should be noted in various embodiments, the processor circuit 406does not partition and/or process a payload of the data packet 742 a.

The processor circuit 406 may output the data packet 746 a to the RFcircuit 420 via the I/O interface 414 to be transmitted along the datachannel of the bi-directional communication link 104. As describedabove, the data packet 746 a may correspond to the anchor point definingthe communication interval 748.

The RF circuit 110 receives the data packet and outputs the data packet746 a to the microcontroller 160. The microcontroller 160 may partitionthe payload from the data packet 746 a and carries out the instructionof the external device 201 from the payload by comparing theinstructions to a stored instruction and/or command set on the memory194 for the wireless protocol.

The microcontroller 160 constructs a data packet 744 a with a payloadcorresponding to the instructions of the external device 201 conformingto the wireless protocol of the bi-directional communication link 104.The microcontroller 160 transmits the data packet 744 a via the RFcircuit 110 within the communication interval 748.

The RF circuit 420 receives and outputs the data packet 744 a to theprocessor circuit 406. The processor circuit 406 may partition andreplace the address information of the data packet 744 a thatcorresponds to the wireless bridge device 102 with the addressinformation of the external device 102, constructing the data packet 746b. The processor circuit 406 outputs the data packet 746 b to the RFcircuit 420 via the I/O interface 414 to be transmitted along the datachannel of the bi-directional communication link 105.

The external device 201 receives the data packet 746 b via the RFcircuit 354 within the communication interval 732. The RF circuit 354outputs the data packet 746 a to the CPU 302 and/or 352. The CPU 302and/or 352 may partition the payload from the data packet 746 b andcarries out the instruction of the external device 201 from the payloadby comparing the instructions to a stored instruction and/or command seton the ROM 304, RAM 306, and/or hard drive 308 for the wirelessprotocol.

Optionally, the data packet 742 a received by the wireless bridge device102 is over a first dedicated data channel of the bi-directionalcommunication link 105, and the data packet 746 a is transmitted fromthe wireless bridge device 102 to the IMD 101 over a second dedicateddata channel of the bi-directional communication link 104.

Optionally, the length of the communication interval 732 may be based ona command action from the user and/or within the payload of the seriesof data packets 742. For example, the user may instruct the externaldevice 201 to transmit a command action to the IMD 101, such as programthe IMD 101, receive measurements from the IMD 101, request a statusupdate of the IMD 101, and/or the like. Each of the command actions maycorrespond to differing lengths of data packets being transmitted fromthe IMD 101 and/or the external device 201. For example, the series ofdata packets 742 from the external device 201 may have larger payloadsrelative to the series of data packets 744 from the IMD 101. In anotherexample, the series of data packets 744 from the IMD 101 may have largerpayloads relative to the series of data packets 742. In variousembodiments, the payloads for each

The length of the communication interval 732 may vary depending on thesize of the payloads from the external device 201 and/or the IMD 101based on the command action. For example, a length of the communicationinterval 732 may be smaller when the user instructs the external device201 to program the IMD 101 relative to communication intervalscorresponding to command actions of measurement requests from the IMD101.

Returning to FIG. 5, at 506 a data packet (e.g., 710, 742) from theexternal device 201 is received at the wireless bridge 102 during acommunication interval (e.g., 732). For example, the wireless bridgedevice 102 may receive the data packet 742 a from the external device201 over a first dedicated data channel of the bi-directionalcommunication link 105.

At 508, the data packet (e.g., 746) from the wireless bridge device 102is transmitted to the IMD 101 during the communication interval (e.g.,732). For example, the wireless bridge device 102 may transmit the datapacket 746 a to the IMD 101 over a second dedicated data channel of thebi-directional communication link 104 during the communication interval732.

At 510, a second data packet (e.g., 744) from the IMD 101 is received atthe wireless bridge device 102 during the communication interval (e.g.,732). For example, the wireless bridge device 102 may receive the datapacket 744 a from the IMD 101 over the second dedicated data channel ofthe bi-directional communication link 104 during the communicationinterval 732.

At 512, the second data packet (e.g., 746) for the wireless bridgedevice 102 is transmitted to the external device 201 during thecommunication interval (e.g., 732). For example, the wireless bridgedevice 102 may transmit the data packet 746 b to the external device 201over the first dedicated data channel of the bi-directionalcommunication link 105 during the communication interval 732.

Various embodiments described herein may implement the method 800illustrated in FIG. 8. Beginning at 802, the wireless bridge device 102may be activated. For example, the wireless bridge device 102 may enterinto an advertisement mode such that the wireless bridge device 102broadcasts one or more advertisement notices 605 along one or morededicated advertisement channels defined by the wireless protocol.

At 804, the wireless bridge device 102 may continually broadcast the oneor more advertisement notices 605 until a connection request is receivedby the external device 201 (master 0).

At 806, when the connection request is received by the wireless bridgedevice 102, the wireless bridge device 102 is connected to the externaldevice 201 over the bi-directional communication link 105. Thebi-directional communication link 105 may be configured with theexternal device 201 as a master device, such as master 0, and thewireless bridge device 102 as a slave device, such as slave 0.

At 808, the wireless bridge device 102 may scan one or moreadvertisement channels for the one or more advertisement notices 705transmitted by the IMD 101.

Optionally, when the wireless device 102 is connected to the externaldevice 201, the external device 201 may transmit connection information(e.g. a serial number) from the IMD 101. The connection information maybe used by the wireless bridge device 102 to establish a connection withthe IMD 101.

Additionally or alternatively, the wireless bridge device 102 may scanone or more advertisement channels for one or more advertisement noticesthat originate from one or more peripheral devices, respectively. Theone or more peripheral devices may correspond to one or more IMDs,medical devices, auxiliary devices, imaging system and/or the like thatare transmitting advertisement notices based on the wireless protocol.For example, the RF circuit 420 may continually shift the scan interval603 between select frequencies that correspond to the one or moreadvertisement channels of the wireless protocol. When the wirelessbridge device 102 receives the one or more advertisement notices (e.g.,705), the processor circuit 406 may store the one or more advertisementnotices on the memory module 408.

The wireless bridge device 102 may generate a list of select peripheralsfrom the one or more peripheral devices detected. The select peripheralsmay correspond to one or more IMDs and/or other medical devices thewireless bridge device 102 may form a bi-directional communication link.For example, the memory module 408 may include a list of manufacturers,product serial numbers, and/or the like of identificationcharacteristics of the select peripheral devices. The processor circuit406 may compare the identification characteristics with theidentification characteristics of the detected peripheral devices basedfrom the one or more advertisement notices.

For example, the processor circuit 406 may partition the payload fromthe one or more advertisement notices stored on the memory module 408.The processor circuit 406 may compare the one or more partitionedpayloads with the protocol syntax on the memory module 408 to determineidentification information, such as manufacturer or product serialnumbers of the corresponding peripheral. The processor circuit 406determines which detected peripheral is a select peripheral by comparingthe identification information stored on the memory module 408. If theidentification information of the detected peripheral matches theidentification information stored on the memory module 408, theprocessor circuit 406 may include the detected peripheral to the list.

The wireless bridge device 102 may transmit the list to the externaldevice 201 over the bi-directional communication link 105. The list maybe displayed on the display 322 of the external device 201. The user mayselect from the displayed list using the touchscreen 324 or standardkeyboard 326 one of the select peripheral devices, such as the IMD 101,to be connected with the wireless bridge device 102 over thebi-directional communication link 104. When the select peripheral deviceis selected, the external device 201 may transmit instructions for thewireless bridge device 102 to establish the bi-directional communicationlink 104 with the selected peripheral device.

At 810, the wireless bridge device 102 establishes the bi-directionalcommunication link 104 with the IMD 101. For example, the wirelessbridge device 102 may transmit a connection request to the IMD 101 inresponse the one or more advertisement notices 705. The bi-directionalcommunication link 104 may be configured with the wireless bridge device102 as a master device, and the IMD 101 as a slave device, such as slave1.

At 812, the wireless bridge device 102 passes or transmits data packets(e.g., the data packets 746 corresponding to the data packets 742)received from the external device 201 (master 0) to the IMD 101(slave 1) and data packets (e.g., the data packets 746 corresponding tothe data packets 744) received from the IMD 101 (slave 1) to theexternal device 201 (master 0). The wireless bridge device 102 maycontinually transmit the data packets 746 until a termination request752 is received from the external device 201.

At 814, the wireless bridge device 102 closes the upper stream link(e.g., the bi-directional communication link 105). The wireless bridgedevice 102 receives the termination request 752 from the external device201. For example, the termination request 752 may be included in a datapacket received by the RF circuit 420. The RF circuit 420 may output thedata packet to the processor circuit 406. The processor circuit 406 mayverify the termination request 752 by comparing particular frames of thedata packet (e.g., a header of the data packet), the payload of the datapacket, and/or the like. When the processor circuit 406 verifies thetermination request 752, the processor circuit 406 may terminate orclose the bi-directional communication link 105. For example, after thebi-directional communication link 105 is terminated the processorcircuit 406 may ignore data packets having address informationcorresponding to the external device 201. Optionally, the processorcircuit 406 may instruct the RF circuit 420 to transmit a confirmationdata packet 754 to the external device 201.

At 816, the wireless bridge device 102 closes the downstream link (e.g.,the bi-directional communication link 104). The wireless bridge maytransmit the termination request 756 to the IMD 101. For example, thewireless bridge device 102 may retransmit the data packet of thetermination request 752 to the IMD 101. The RF circuit 110 may outputthe data packet to the microcontroller 160. The microcontroller 160 mayverify the termination request 756 by comparing particular frames of thedata packet (e.g., a header of the data packet), the payload of the datapacket, and/or the like. When the microcontroller 160 verifies thetermination request 756, the microcontroller 160 may terminate or closethe bi-directional communication link 104. For example, after thebi-directional communication link 104 is terminated, the microcontroller160 may or data packets having address information corresponding to thewireless bridge device 102. Optionally, the microcontroller 160 mayinstruct the RF circuit 110 to transmit a confirmation data packet 758to the wireless bridge device 102.

Additionally or alternatively, when the bi-directional communicationlinks 104 and 105 have been terminated or closed, the wireless bridgedevice may continually broadcast the one or more advertisement notices605 over one or more advertisement channels (e.g., 804).

Additionally or alternatively, when the bi-directional communicationlink 104 has been terminated or closed, the IMD 101 may continuallybroadcast the one or more advertisement notices 705 over one or moreadvertisement channels.

FIG. 9 illustrates a block diagram of exemplary internal components ofthe IMD 900, in accordance with an embodiment. For example, the IMD 900may be a neurostimulator adapted to stimulate spinal cord tissue,peripheral nerve tissue, deep brain tissue, cortical tissue, cardiactissue, digestive tissue, pelvic floor tissue, or any other suitablenerve tissue of interest within a patient's body.

The IMD 900 may include an implantable pulse generator (IPG) 950 that isadapted to generate electrical pulses applied to the tissue of apatient. Additionally or alternatively, the IPG 950 may be an externalneuro pulse generator. The IPG 950 typically comprises a metallichousing that encloses a controller 951, pulse generating circuitry 952,a charging coil 953, a battery 954, RF circuit 955, battery chargingcircuitry 956, switching circuitry 957, memory 958, and the like.

The controller 951 (also referred to herein as a processor module orunit) typically includes a microprocessor, or equivalent controlcircuitry, designed specifically for controlling the components of theIPG 950 and may further include RAM or ROM memory, logic and timingcircuitry, state machine circuitry, and I/O circuitry. Typically, thecontroller 951 includes the ability to process or monitor input signals(data) as controlled by program code stored in memory. The details ofthe design and operation of the controller 951 are not critical to theinvention. Rather, any suitable controller 951 may be used that carriesout the functions described herein.

The IPG 950 may comprise a separate or an attached extension component970. If the extension component 970 is a separate component, theextension component 970 may connect with a “header” portion of the IPG950 as is known in the art. If the extension component 970 is integratedwith the IPG 950, internal electrical connections may be made throughrespective conductive components. Within the IPG 950, electrical pulsesare generated by the pulse generating circuitry 952 and are provided tothe switching circuitry 957. The switching circuitry 957 connects tooutputs of the IPG 950. Electrical connectors (e.g., “Bal-Seal”connectors) within the connector portion 971 of the extension component970 or within the IPG header may be employed to conduct variousstimulation pulses. The terminals of one or more leads 910 are insertedwithin connector portion 971 or within the IPG header for electricalconnection with respective connectors. Thereby, the pulses originatingfrom the IPG 950 are provided to the leads 910. The pulses are thenconducted through the conductors of the lead 910 and applied to tissueof a patient via stimulation electrodes 911 that may be coupled toblocking capacitors. Any suitable known or later developed design may beemployed for connector portion 971.

The stimulation electrodes 911 may be positioned along a horizontal axis902 of the lead 910, and are angularly positioned about the horizontalaxis 802 so the stimulation electrodes 911 do not overlap. Thestimulation electrodes 911 may be in the shape of a ring such that eachstimulation electrode 911 continuously covers the circumference of theexterior surface of the lead 910. Each of the stimulation electrodes 911are separated by non-conducting rings 912, which electrically isolateeach stimulation electrode 911 from an adjacent stimulation electrode911. The non-conducting rings 912 may include one or more insulativematerials and/or biocompatible materials to allow the lead 910 to beimplantable within the patient. Non-limiting examples of such materialsinclude polyimide, polyetheretherketone (PEEK), polyethyleneterephthalate (PET) film (also known as polyester or Mylar),polytetrafluoroethylene (PTFE) (e.g., Teflon), or parylene coating,polyether bloc amides, polyurethane. The stimulation electrodes 911 maybe configured to emit the pulses in an outward radial directionproximate to or within a stimulation target. Additionally oralternatively, the stimulation electrodes 911 may be in the shape of asplit or non-continuous ring such that the pulse may be directed in anoutward radial direction adjacent to the stimulation electrodes 911.Examples of a fabrication process of the stimulation electrodes 911 isdisclosed in U.S. patent application Ser. No. 12/895,096, entitled,“METHOD OF FABRICATING STIMULATION LEAD FOR APPLYING ELECTRICALSTIMULATION TO TISSUE OF A PATIENT,” which is expressly incorporatedherein by reference.

It should be noted the stimulation electrodes 911 may be in variousother formations, for example, in a planar formation on a paddlestructure as disclosed in U.S. Provisional Application No. 61/791,288,entitled, “PADDLE LEADS FOR NEUROSTIMULATION AND METHOD OF DELIVERINGTHE SAME,” which is expressly incorporated herein by reference.

The lead 910 may comprise a lead body 972 of insulative material about aplurality of conductors within the material that extend from a proximalend of lead 910, proximate to the IPG 950, to its distal end. Theconductors electrically couple a plurality of the stimulation electrodes911 to a plurality of terminals (not shown) of the lead 910. Theterminals are adapted to receive electrical pulses and the stimulationelectrodes 911 are adapted to apply the pulses to the stimulation targetof the patient. Also, sensing of physiological signals may occur throughthe stimulation electrodes 911, the conductors, and the terminals. Itshould be noted that although the lead 910 is depicted with fourstimulation electrodes 911, the lead 910 may include any suitable numberof stimulation electrodes 911 (e.g., less than four, more than four) aswell as terminals, and internal conductors. Additionally oralternatively, various sensors (e.g., a position detector, a radiopaquefiducial) may be located near the distal end of the lead 910 andelectrically coupled to terminals through conductors within the leadbody 972.

For implementation of the components within the IPG 950, a processor andassociated charge control circuitry for an IPG is described in U.S. Pat.No. 7,571,007, entitled “SYSTEMS AND METHODS FOR USE IN PULSEGENERATION,” which is expressly incorporated herein by reference.Circuitry for recharging a rechargeable battery (e.g., battery chargingcircuitry 956) of an IPG 950 using inductive coupling and externalcharging circuits are described in U.S. Pat. No. 7,212,110, entitled“IMPLANTABLE DEVICE AND SYSTEM FOR WIRELESS COMMUNICATION,” which isexpressly incorporated herein by reference.

An example and discussion of “constant current” pulse generatingcircuitry (e.g., pulse generating circuitry 952) is provided in U.S.Patent Publication No. 2006/0170486 entitled “PULSE GENERATOR HAVING ANEFFICIENT FRACTIONAL VOLTAGE CONVERTER AND METHOD OF USE,” which isexpressly incorporated herein by reference. One or multiple sets of suchcircuitry may be provided within the IPG 950. Different pulses ondifferent stimulation electrodes 911 may be generated using a single setof the pulse generating circuitry 952 using consecutively generatedpulses according to a “multi-stimset program” as is known in the art.Complex pulse parameters may be employed such as those described in U.S.Pat. No. 7,228,179, entitled “Method and apparatus for providing complextissue stimulation patterns,” and International Patent PublicationNumber WO 2001/093953 A1, entitled “NEUROMODULATION THERAPY SYSTEM,”which are expressly incorporated herein by reference. Alternatively,multiple sets of such circuitry may be employed to provide pulsepatterns (e.g., tonic stimulation waveform, burst stimulation waveform)that include generated and delivered stimulation pulses through variousstimulation electrodes of one or more leads 911 as is also known in theart. Various sets of parameters may define the pulse characteristics andpulse timing for the pulses applied to the various stimulationelectrodes 911 as is known in the art. Although constant current pulsegenerating circuitry is contemplated for some embodiments, any othersuitable type of pulse generating circuitry may be employed such asconstant voltage pulse generating circuitry.

The stimulation parameters (e.g., amplitude, frequency, type ofstimulation waveform) and other operating parameters of the IMD 900 maybe non-invasively programmed into the memory 958 through the RF circuit955 in bi-directional wireless communication link 104. For example, theexternal device 201 may permit the user to move electrical stimulationalong and/or across one or more of the lead(s) 910 using differentstimulation electrode 911 combinations by communicating to the IMD 900via the wireless bridge device 102, for example, as described in U.S.Patent Application Publication No. 2009/0326608, entitled “METHOD OFELECTRICALLY STIMULATING TISSUE OF A PATIENT BY SHIFTING A LOCUS OFSTIMULATION AND SYSTEM EMPLOYING THE SAME,” which is expresslyincorporated herein by reference. The controller 951 controls the RFcircuit 955 and receives data/transmissions from the RF circuit 955. TheRF circuit 955 further allows status information relating to theoperation of IMD 900 (as contained in the controller 951 or memory 958)to be sent to via the bi-directional communication link 104.

The controller 951 may support a particular wireless communicationprotocol while communicating with the wireless bridge device 102 and/orthe external device 201, such as Bluetooth low energy, Bluetooth,ZigBee, Medical Implant Communication Service (“MICS”), or the like.Protocol firmware may be stored in memory 958, which is accessed by thecontroller 951. The protocol firmware provides the wireless protocolsyntax for the controller 951 to assemble data packets, establishcommunication links 104, and partition data received from thebi-directional communication link 104.

The memory 958 may also contain a pre-defined algorithm that generates apasskey. The passkey may be used to initiate a bonding procedure betweenthe IMD 900 and the external device 201 to establish a securedbi-directional communication session over the bi-directionalcommunication link 104. The passkey may be generated based on a dynamicseed and/or a static identification received by the RF circuit 955through the bi-directional communication link 104 from the wirelessbridge device 102 and inputted into the pre-defined algorithm.Optionally, the dynamic seed may be a random number generated by thecontroller 951, based on the local system clock of the IMD 900, or thelike that is transmitted by the RF circuit 955 to the external device.Additionally or alternatively, the static identification may be storedon the memory 958 representing a product serial identification number ofthe IMD 900, which is a unique number assigned to the IMD 900 by amanufacturer of the IMD 900. Optionally, the static identification maybe a pre-determined number stored on the memory 958 set by a user.

The controller 951, the processor circuit 406, the microcontroller 160,and CPUs 302 and 352 may include any processor-based ormicroprocessor-based system including systems using microcontrollers,reduced instruction set computers (RISC), application specificintegrated circuits (ASICs), field-programmable gate arrays (FPGAs),logic circuits, and any other circuit or processor capable of executingthe functions described herein. Additionally or alternatively, thecontroller 951, the processor circuit 406, the microcontroller 160, andCPUs 302 and 352 represent circuit modules that may be implemented ashardware with associated instructions (for example, software stored on atangible and non-transitory computer readable storage medium, such as acomputer hard drive, ROM, RAM, or the like) that perform the operationsdescribed herein. The above examples are exemplary only, and are thusnot intended to limit in any way the definition and/or meaning of theterm “controller.” The controller 951, the processor circuit 406, themicrocontroller 160, and CPUs 302 and 352 may execute a set ofinstructions that are stored in one or more storage elements, in orderto process data. The storage elements may also store data or otherinformation as desired or needed. The storage element may be in the formof an information source or a physical memory element within thecontroller 951, the processor circuit 406, the microcontroller 160, andCPUs 302 and 352. The set of instructions may include various commandsthat instruct the controller 951, the processor circuit 406, themicrocontroller 160, and CPUs 302 and 352 to perform specific operationssuch as the methods and processes of the various embodiments of thesubject matter described herein. The set of instructions may be in theform of a software program. The software may be in various forms such assystem software or application software. Further, the software may be inthe form of a collection of separate programs or modules, a programmodule within a larger program or a portion of a program module. Thesoftware also may include modular programming in the form ofobject-oriented programming. The processing of input data by theprocessing machine may be in response to user commands, or in responseto results of previous processing, or in response to a request made byanother processing machine.

It is to be understood that the subject matter described herein is notlimited in its application to the details of construction and thearrangement of components set forth in the description herein orillustrated in the drawings hereof. The subject matter described hereinis capable of other embodiments and of being practiced or of beingcarried out in various ways. Also, it is to be understood that thephraseology and terminology used herein is for the purpose ofdescription and should not be regarded as limiting. The use of“including,” “comprising,” or “having” and variations thereof herein ismeant to encompass the items listed thereafter and equivalents thereofas well as additional items.

It is to be understood that the above description is intended to beillustrative, and not restrictive. For example, the above-describedembodiments (and/or aspects thereof) may be used in combination witheach other. In addition, many modifications may be made to adapt aparticular situation or material to the teachings of the inventionwithout departing from its scope. While the dimensions, types ofmaterials and coatings described herein are intended to define theparameters of the invention, they are by no means limiting and areexemplary embodiments. Many other embodiments will be apparent to thoseof skill in the art upon reviewing the above description. The scope ofthe invention should, therefore, be determined with reference to theappended claims, along with the full scope of equivalents to which suchclaims are entitled. In the appended claims, the terms “including” and“in which” are used as the plain-English equivalents of the respectiveterms “comprising” and “wherein.” Moreover, in the following claims, theterms “first,” “second,” and “third,” etc. are used merely as labels,and are not intended to impose numerical requirements on their objects.Further, the limitations of the following claims are not written inmeans—plus-function format and are not intended to be interpreted basedon 35 U.S.C. §112(f), unless and until such claim limitations expresslyuse the phrase “means for” followed by a statement of function void offurther structure.

What is claimed is:
 1. A method for bridging a bi-directionalcommunication link between an external device and an implantable medicaldevice (IMD), the method comprising: establishing a first bi-directionalcommunication link between an external device and a wireless bridgedevice according to a wireless protocol; establishing a secondbi-directional communication link between the wireless bridge device andan IMD concurrently with the first bi-directional communication linkaccording to the wireless protocol, wherein the wireless protocolestablishes a communication link between the wireless bridge device andthe IMD according to at least one of a Bluetooth protocol, a Bluetoothlow energy protocol, or a ZigBee protocol; receiving a data packet fromthe external device at the wireless bridge device, wherein the datapacket is received during a communication interval; and transmitting thedata packet from the wireless bridge device to the IMD during thecommunication interval.
 2. The method of claim 1, further comprising:receiving a second data packet from the IMD at the wireless bridgedevice during the communication interval; and transmitting the seconddata packet from the wireless bridge device to the external deviceduring the communication interval.
 3. The method of claim 1, wherein thecommunication interval is subdivided into time slices, at least one ofthe time slices corresponding to the transmitting operation of the datapacket from the wireless bridge device to the IMD.
 4. The method ofclaim 1, wherein a length of the communication interval is based on acommand action, wherein the command action corresponds to at least oneof program the IMD, receive measurements from the IMD, or request astatus update of the IMD.
 5. The method of claim 1, further comprising:receiving connection identification information from the external deviceover the first bi-directional communication link, wherein the connectionidentification information corresponds to the IMD and is used toestablish the second bi-directional communication link.
 6. The method ofclaim 1, further comprising: configuring the wireless bridge device toenter an advertisement mode, wherein during the advertisement mode thewireless bridge device broadcasts one or more advertisement noticesalong a dedicated advertisement channel defined by the wirelessprotocol; detecting at least one of the one or more advertisementnotices at the external device, wherein the first bi-directionalcommunication link is established based on the at least one of the oneor more advertisement notices.
 7. The method of claim 1, furthercomprising: configuring the first bi-directional communication link tohave the external device in a master configuration and the wirelessbridge device in a slave configuration as defined by the wirelessprotocol; and configuring the second bi-directional communication linkto have the wireless bridge device in a master configuration and the IMDin a slave configuration as defined by the wireless protocol.
 8. Amethod for bridging a bi-directional communication link between anexternal device and an implantable medical device (IMD), the methodcomprising: establishing a first bi-directional communication linkbetween an external device and a wireless bridge device according to awireless protocol; establishing a second bi-directional communicationlink between the wireless bridge device and an IMD concurrently with thefirst bi-directional communication link according to the wirelessprotocol; scanning one or more advertisement channels by the wirelessbridge device for one or more advertisement notices that originate fromone or more peripheral devices, respectively; and generating a list ofselect peripherals from the one or more peripheral devices, wherein atleast one of the select peripherals is the IMD.
 9. The method of claim8, further comprising: transmitting the list from the wireless bridge tothe external device; and selecting the IMD from the list at the externaldevice.
 10. The method of claim 1, wherein the wireless bridge deviceincludes a Bluetooth Low Energy System on Chip.
 11. The method of claim1, wherein the wireless protocol establishes a communication linkbetween the wireless bridge device and the external device according toat least one of a Bluetooth protocol, a Bluetooth low energy protocol,or a ZigBee protocol.
 12. The method of claim 1, further comprising:configuring the IMD to enter an advertisement mode, wherein during theadvertisement mode the IMD broadcasts one or more advertisement noticesalong a dedicated advertisement channel defined by the wirelessprotocol; detecting at least one of the one or more advertisementnotices at the wireless bridge device, wherein the second bi-directionalcommunication link is established based on the at least one of the oneor more advertisement notices.
 13. The method of claim 1, furthercomprising: receiving a termination request from the external device atthe wireless bridge device; and transmitting the termination request tothe IMD from the wireless bridge device.
 14. A wireless bridge devicefor bridging a bi-directional communication link between an externaldevice and an implantable medical device (IMD) comprising: a housing; atleast one antenna; and a System on Chip (SoC) within the housingelectrically coupled to the at least one antenna, the SoC includes oneor more processors and is configured to: establish a firstbi-directional communication link with an external device according to awireless protocol, establish a second bi-directional communication linkwith an IMD concurrently with the first bi-directional communicationlink according to the wireless protocol, wherein the secondbi-directional communication link with the IMD uses at least one of aBluetooth protocol, a Bluetooth low energy protocol, or a ZigBeeprotocol, receive a data packet from the external device via the atleast one antenna during a communication interval, and transmit the datapacket to the IMD via the at least one antenna during the communicationinterval.
 15. The wireless bridge device of claim 14, wherein the SoC isfurther configured to: receive a second data packet from the IMD via theat least one antenna during the communication interval; and transmit thesecond data packet to the external device via the at least one antennaduring the communication interval.
 16. The wireless bridge device ofclaim 14, wherein the communication interval is subdivided into timeslices, at least one of the time slices corresponding to thetransmitting operation of the data packet from the wireless bridgedevice to the IMD.
 17. The wireless bridge device of claim 14, whereinthe SoC is further configured to: receive connection identificationinformation from the external device over the first bi-directionalcommunication link, wherein the connection identification informationcorresponds to the IMD and is used to establish the secondbi-directional communication link.
 18. The wireless bridge device ofclaim 14, wherein the SoC is further configured to: enter anadvertisement mode, wherein during the advertisement mode the at leastone antenna broadcasts one or more advertisement notices along adedicated advertisement channel defined by the wireless protocol; anddetect a connection request from the external device during theadvertisement mode, wherein the first bi-directional communication linkis established based on the detection request.
 19. The wireless bridgedevice of claim 14, wherein the SoC is further configured to: operate ina slave configuration with respect to the external device correspondingto the first bi-directional communication link as defined by thewireless protocol; and operate in a master configuring with respect tothe IMD corresponding to the second bi-directional communication link asdefined by the wireless protocol.
 20. The wireless bridge device ofclaim 14, wherein the SoC is further configured to: scan one or moreadvertisement channels for one or more advertisement notices thatoriginate from one or more peripheral devices; and generate a list ofselect peripherals from the one or more peripheral devices, wherein atleast one of the select peripherals is the IMD.